With the interest in mountain biking gaining in popularity a new type of trail system is emerging; trails that are designed specifically for two wheeled cycles. Such trails have an incline with banked corners and obstacles of dirt, rock and wood which are fashioned to either propel the bike and rider into the air or test the rider's balance. Such trails are often rough, narrow, and have sharp turns. Therefore, to ride these trails mountain bikes have acquired long travel independent suspension systems, disc brakes that do not compromise suspension performance and special steering geometry.
New ways to experience these trails are inevitable. With the current popularity of surfing, snow boarding, skateboarding, mountain boarding and inline boarding it is fitting that a vehicle that would allow a person to ride these trails standing in a surfing manner would be desirable. However, conventional mountain boards are unable to navigate these single track trails effectively because such boards are double tracked, have small wheels, little ground clearance and minimal suspension travel. Although conventional inline boards are single tracked and offer larger wheels, they are also insufficient because most lack independent suspension, adequate suspension travel, and a wheel base that allows for adequate ground clearance and for sharp turns.
It is therefore an intent of this invention to produce an inline board that can be ridden in a surfing stance on rough, narrow, and winding single track trails. It is comprised of two relatively large diameter wheels positioned lengthwise in-line with each other. The wheels rotate about axes which are parallel in relation to each other and lateral in relation to the length of the board. The front wheel articulates so that it can be steered by tilting the deck into the direction of intended travel. Both wheels are able to move vertically to travel over uneven surfaces and to absorb the impact of harsh landings resulting from various obstacles. The center of gravity is low, while permitting a relatively large range of vertical wheel travel. A suspension system is provided that does not alter steering geometry.
The steering system of this invention is an improvement over that of my U.S. Pat. No. 6,926,294 B2. The steering system of U.S. Pat. No. 6,926,294 B2 steers very responsively as long as the board is tilted laterally left or right at small degrees off of the horizontal plane. However, after the board of U.S. Pat. No. 6,926,294 B2is tilted beyond these initial degrees away from horizontal the steering becomes less and less responsive until ultimately the front wheel will not turn further at all and, with further tilting, returns to a straight-ahead alignment. My present invention improves the steering system of U.S. Pat. No. 6,926,294 B2 so that it will provide responsive steering even when the board is tilted left or right at more extreme angles away from the horizontal plane, and so that it will self-align once the board is returned to the horizontal plane and will provide a stable predictable means of regulating the movement of the steering assembly.
In the prior art, I am also aware of German Patent DE 101,00,072 B4. The German board in German Patent DE 101,00,072 B4 (herein the “German board”) varies the angle of the steering axis. The angle of steering axis on my board is constant. What varies on my board is the forward offset of my front wheel in relation to the steering axis. The wheel base remains constant on the German board when it is turned. My wheel base is decreased as it is steered away from straight ahead.
The differences are significant when it comes to the performance of the boards. At straight ahead alignment the German board has a steep steering angle. As the board is turned away from straight ahead the steering angle is leaned backwards. It is well established in the bicycle world that a steeper steering angle will produce a smaller turning radius and snappier steering. For example: Cross Country bikes generally have 71 degree steering axis angle for slow speeds and tight turns. On the other hand, Down Hill bikes can have as little as a 63 degree steering axis angle for larger radius turns at higher speeds. My point is that the German board starts to turn with a tight steering radius and as it is leaned increases its turning radius. In other words, the more the board is leaned the less the board will turn.
To perform a tight turn on my deck the deck must be tilted far away from horizontal. To perform a large radius high speed turn the deck must only be tilted a little off horizontal.
The steering characteristics of the German board are counter intuitive. Most popular board sports like surfing, skateboarding, snowboarding, and wakeboarding operate on the principle that as the tilt of the board is increased away from horizontal the turning radius is decreased. My board works on this principle. My steering axis angle remains constant but as the board is tilted away from horizontal the wheel becomes more responsive to turning, therefore, reducing the turning radius.